Data is increasingly transmitted via fiber optic cables. Conduit systems are used to facilitate the underground installation of fiber optic cable networks. Typically, a conduit section includes a plurality of innerducts housed in an outer duct, and each section is connected end-to-end with a like section to form a continuous conduit network. The conduit sections are preferably joined together at the installation site therefore it is highly desirable to be able to interconnect them in one efficient and reliable operation.
It is also important to achieve an air and water tight seal between the adjacent innerducts when conduit sections are interconnected. A water fight seal reduces data transmission problems, while an air fight conduit network increases the uninterrupted distance over which conventional fiber optic cable threading procedures can be carried out.
Seiter, U.S. Pat. No. 5,078,432, describes a system employing multiple duct conduit sections and separate couplers to connect adjacent sections. The outer couplers have a double-ended belled housing to connect adjacent sections together, while an inner coupler is used for connecting the inner ducts of adjacent sections. The inner coupling described in the Seiter patent comprises a one-piece receptacle including a flange with a plurality of cylindrical sockets extending in both directions for receiving the inner ducts, and O-rings seated in grooves therein for forming a seal around the inner ducts of an abutting conduit section when the inner ducts are pushed through. The annular seal means, or O-rings, must be individually mounted within the receptacle and may dislodge when an inner duct is pushed through thus compromising the integrity of the conduit system; while it requires increased time and expense to perform the assembly of the conduit system which involves separate coupling members.